Input/output apparatus of multiplexer, and multiplexer

ABSTRACT

An input/output apparatus of a multiplexer is provided, including: a main tap and at least two branch taps of the main tap, where each of the at least two branch taps is configured to couple to a different resonant cavity in the multiplexer, and the at least two branch taps include a first branch tap and a second branch tap; a coupling polarity of the first branch tap is opposite to that of the second branch tap; and a coupling calculation frequency of the second branch tap is closest to a coupling calculation frequency of the first branch tap. The input/output apparatus of the multiplexer enables two channels with closest frequencies to use different coupling polarities. Because the coupling polarities are different, signals naturally do not interfere with each other, and signal interference between channels is eliminated in principle. The embodiments of the present disclosure further provide a corresponding multiplexer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2016/075607, filed on Mar. 4, 2016, which claims priority toChinese Patent Application No. 201510214812.0, filed on Apr. 29, 2015.The disclosures of the aforementioned applications are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates to the field of multiplexer technologies,and in particular, to an input/output apparatus of a multiplexer, and amultiplexer.

BACKGROUND

As communications base stations are highly integrated, there is agrowing demand for multiplexers. For a multiplexer, a core technology isan input/output apparatus of the multiplexer. In the prior art, each tapin an input/output apparatus is connected to a resonant cavity by meansof welding.

From a perspective of receiving signals by a base station, a signalreceived by an antenna enters a multiplexer from an input/outputapparatus of the multiplexer; and signals of different frequencies flowinto multiplexer channels of different frequencies. Because a differencebetween the frequencies of the signals on the channels is generallysmall, signal interference between the channels is very high. Incontrast, from a perspective of outputting signals from the multiplexer,the same applies to a reverse process, that is, signal interferencebetween the channels is very high.

In the prior art, to reduce signal interference between channels, a flylever is added to a resonant cavity for phase adjustment. Signalinterference between channels is reduced by means of phase adjustment.However, because phase adjustment is hard in this mode, signalinterference between channels cannot be completely eliminated.

SUMMARY

Embodiments of the present disclosure provide an input/output apparatusof a multiplexer, and a multiplexer, so as to eliminate signalinterference between different channels in a multiplexer.

A first aspect of the present disclosure provides an input/outputapparatus of a multiplexer, including:

a main tap and at least two branch taps of the main tap, where

each of the at least two branch taps is configured to couple to adifferent resonant cavity in the multiplexer, and the at least twobranch taps include a first branch tap and a second branch tap; and

a coupling polarity of the first branch tap is opposite to that of thesecond branch tap, and a coupling calculation frequency of the secondbranch tap is closest to a coupling calculation frequency of the firstbranch tap.

With reference to the first aspect, in a first possible implementation,

an arrangement of the at least two branch taps includes at least twolayers in a vertical direction.

With reference to the first aspect or the first possible implementationof the first aspect, in a second possible implementation,

the first tap is capacitively coupled, and the second tap is inductivelycoupled; or, the first tap is inductively coupled, and the second tap iscapacitively coupled.

A second aspect of the present disclosure provides a multiplexer,including: an input/output apparatus, a resonant cavity, and a mountingplate, where the resonant cavity is disposed into the mounting plate;

the input/output apparatus includes a main tap and at least twofirst-level branch taps of the main tap, where each of the at least twofirst-level branch taps is coupled to a different first-level resonantcavity, and the at least two first-level branch taps include a firstfirst-level branch tap and a second first-level branch tap; and

a coupling polarity of the first first-level branch tap is opposite tothat of the second first-level branch tap, and a coupling calculationfrequency of the second first-level branch tap is closest to a couplingcalculation frequency of the first first-level branch tap.

With reference to the second aspect, in a first possible implementation,at least one first-level resonant cavity is connected to at least twosecond-level branch taps, where each of the at least two second-levelbranch taps is coupled to a different second-level resonant cavity, andthe at least two second-level branch taps include a first second-levelbranch tap and a second second-level branch tap; and

a coupling polarity of the first second-level branch tap is opposite tothat of the second second-level branch tap, and a coupling calculationfrequency of the second second-level branch tap is closest to a couplingcalculation frequency of the first second-level branch tap.

With reference to the second aspect or the first possible implementationof the second aspect, in a second possible implementation, anarrangement of the first-level branch taps includes at least two layersin a vertical direction.

With reference to the second aspect or the first or the second possibleimplementation of the second aspect, in a third possible implementation,

a boss is disposed on the mounting plate, and the boss is configured tophysically connect to a branch tap to the boss directly when the branchtap is capacitively coupled to a resonant cavity.

With reference to the third possible implementation of the secondaspect, in a fourth possible implementation, an adjustment screw isfurther disposed on the mounting plate, and the adjustment screw isconfigured to adjust coupling strength of capacitive coupling.

With reference to any one of the second aspect, or the first to thefourth possible implementations of the second aspect, in a fifthpossible implementation,

the first first-level branch tap is capacitively coupled, and the secondfirst-level branch tap is inductively coupled; or, the first first-levelbranch tap is inductively coupled, and the second first-level branch tapis capacitively coupled.

A third aspect of the present disclosure provides a multiplexer,including a resonant cavity, where

when there are at least two levels of resonant cavities, each of atleast one first-level resonant cavity is coupled to a differentsecond-level resonant cavity via at least two taps, where the at leasttwo taps include a first tap and a second tap; and

a coupling polarity of the first tap is opposite to that of the secondtap, and a coupling calculation frequency of the second tap is closestto a coupling calculation frequency of the first tap.

With reference to the third aspect, in a first possible implementation,the multiplexer further includes an input/output apparatus, where

a tap of the input/output apparatus is connected to the first-levelresonant cavity.

The input/output apparatus of a multiplexer provided in the embodimentsof the present disclosure includes: a main tap and at least two branchtaps of the main tap, where each of the at least two branch taps isconfigured to couple to a different resonant cavity in the multiplexer,and the at least two branch taps include a first branch tap and a secondbranch tap; a coupling polarity of the first branch tap is opposite tothat of the second branch tap; and a coupling calculation frequency ofthe second branch tap is closest to a coupling calculation frequency ofthe first branch tap. Compared with the prior art in which signalinterference between channels in a multiplexer is reduced by means ofphase adjustment using a fly lever, in the input/output apparatus of amultiplexer provided in the embodiments of the present disclosure, acoupling polarity of the first branch tap is opposite to that of thesecond branch tap; and a coupling calculation frequency of the secondbranch tap is closest to a coupling calculation frequency of the firstbranch tap, so that two channels with closest frequencies use differentcoupling polarities. Because the coupling polarities are different,signals naturally do not interfere with each other, and signalinterference between channels is eliminated in principle.

BRIEF DESCRIPTION OF DRAWINGS

To describe the technical solutions in the embodiments of the presentdisclosure more clearly, the following briefly describes theaccompanying drawings required for describing the embodiments.Apparently, the accompanying drawings in the following description showmerely some embodiments of the present disclosure, and persons skilledin the art may still derive other drawings from these accompanyingdrawings without creative efforts.

FIG. 1 is a schematic principle diagram of an input/output apparatusaccording to an embodiment of the present disclosure;

FIG. 2 is another schematic principle diagram of an input/outputapparatus according to an embodiment of the present disclosure;

FIG. 3 is another schematic principle diagram of an input/outputapparatus according to an embodiment of the present disclosure;

FIG. 4 is a schematic structural diagram of an input/output apparatusaccording to an embodiment of the present disclosure;

FIG. 5 is a schematic principle diagram of a multiplexer according to anembodiment of the present disclosure;

FIG. 6 is another schematic principle diagram of a multiplexer accordingto an embodiment of the present disclosure;

FIG. 7 is a schematic structural diagram of a multiplexer according toan embodiment of the present disclosure;

FIG. 8 is another schematic structural diagram of a multiplexeraccording to an embodiment of the present disclosure;

FIG. 9 is another schematic structural diagram of a multiplexeraccording to an embodiment of the present disclosure;

FIG. 10 is another schematic principle diagram of a multiplexeraccording to an embodiment of the present disclosure; and

FIG. 11 is another schematic structural diagram of a multiplexeraccording to an embodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS

The embodiments of the present disclosure provide an input/outputapparatus of a multiplexer, and a multiplexer, so as to eliminate signalinterference between different channels in the multiplexer. Thefollowing provides respective details.

The following clearly and completely describes the technical solutionsin the embodiments of the present disclosure with reference to theaccompanying drawings in the embodiments of the present disclosure.Apparently, the described embodiments are merely some but not all of theembodiments of the present disclosure. All other embodiments obtained bypersons skilled in the art based on the embodiments of the presentdisclosure without creative efforts shall fall within the protectionscope of the present disclosure.

It should be noted that, the multiplexer provided in the embodiments ofthe present disclosure includes various forms, for example, a duplexer,a tri-plexer, a quad-plexer, or more-channel multiplexer.

The embodiments of the present disclosure achieve an objective ofreducing mutual interference between channels with a same frequency orclose frequencies by using an opposite-polarity coupling method on tapsfor the channels with the same frequency or close frequencies.

FIG. 1, FIG. 2, and FIG. 3 are schematic principle diagrams of aninput/output apparatus according to embodiments of the presentdisclosure. In FIG. 2, a resonant cavity is indicated by a dashed line,meaning that the resonant cavity is a constituent part of themultiplexer instead of a constituent part of the input/output apparatus.As shown in FIG. 1 and FIG. 2, the input/output apparatus of themultiplexer includes: a main tap 11 and at least two branch taps 12 ofthe main tap 11. FIG. 1 and FIG. 2 each show three branch taps. Inpractice, there may be two branch taps, or may be four or more branchtaps. This, however, does not limit a quantity of branch taps of themain channel. As shown in FIG. 2, each of the at least two branch taps12 is configured to couple to a different resonant cavity 21 in themultiplexer. As shown in FIG. 3, it is assumed that there are threebranch taps of the main tap 11: a first branch tap 121, a second branchtap 122, and a third branch tap 123. Certainly, the first, the second,and the third herein do not represent a sequence or definite meanings,but are just for the ease of description. A coupling polarity of thefirst branch tap 121 is opposite to that of the second branch tap 122,and the coupling polarity of the second branch tap 122 is opposite tothat of the third branch tap 123. A coupling calculation frequency ofthe first branch tap 121 is closest to a coupling calculation frequencyof the second branch tap 122, and the coupling calculation frequency ofthe second branch tap 122 is closest to a coupling calculation frequencyof the third branch tap 123.

In this embodiment of the present disclosure, the coupling calculationfrequency is a frequency used when it is determined whether the couplingpolarity of the first branch tap is opposite to that of the secondbranch tap. The coupling calculation frequency may be an operatingfrequency of a resonant cavity to which each tap is connected. Theoperating frequency may be a frequency at a point (for example, 1800 MHzor 900 MHz), or may be a frequency in a frequency band (for example, forapplication in a base station, a transmit frequency band 1805 MHz to1880 MHz of the base station). In practice, usually, a central pointfrequency of a resonant cavity to which each tap is connected (sometimesis a central point frequency of a tap in this embodiment of the presentdisclosure) is used, or the highest frequency and the lowest frequencyof an operating band of the resonant cavity to which each tap isconnected may be compared. For example, when the central point frequencyis used as the coupling calculation frequency, a central point frequencyof the first branch tap 121 is 3 Hz, a central point frequency of thesecond branch tap 122 is 7 Hz, and a central point frequency of thethird branch tap 123 is 13 Hz. It can be learnt that a differencebetween the central point frequency of the first branch tap 121 and thecentral point frequency of the second branch tap 122 is 4 Hz, and adifference between the central point frequency of the first branch tap121 and the central point frequency of the third branch tap 123 is 10Hz. In this way, it can be determined that the central point frequencyof the first branch tap 121 is closest to the central point frequency ofthe second branch tap 122. Therefore, the coupling polarity of the firstbranch tap 121 is opposite to that of the second branch tap 122. Asshown in FIG. 3, it may be set that the first branch tap 121 iscapacitively coupled, and that the second branch tap 122 is inductivelycoupled. Alternatively, certainly, it may be set that the first branchtap 121 is inductively coupled, and that the second branch tap 122 iscapacitively coupled. A difference between the central point frequencyof the third branch tap 123 and the central point frequency of the firstbranch tap 121 is 10 Hz, and a difference between the central pointfrequency of the third branch tap 123 and the central point frequency ofthe second branch tap 122 is 6 Hz. In this way, it may be determinedthat the coupling polarity of the third branch tap 123 is opposite tothat of the second branch tap 122. When the second branch tap 122 isinductively coupled, the third branch tap 123 is capacitively coupled.When the second branch tap 122 is capacitively coupled, the third branchtap 123 is inductively coupled.

It should be noted herein that the closest described in this embodimentof the present disclosure is not limited to only one. For example, whena difference between the central point frequency of the second branchtap 122 and the central point frequency of the first branch tap 121 is 4Hz, and a difference between the central point frequency of the secondbranch tap 122 and the central point frequency of the third branch tap123 is still 4 Hz, it may be considered that the central point frequencyof the second branch tap 122 is closest to both the central pointfrequency of the first branch tap 121 and the central point frequency ofthe third branch tap 123. When the second branch tap is inductivelycoupled, the first branch tap 121 and the third branch tap 123 are bothcapacitively coupled. When the second branch tap is capacitivelycoupled, the first branch tap 121 and the third branch tap 123 are bothinductively coupled.

When the highest and the lowest frequencies of the tap operating bandare used as the coupling calculation frequency, the lowest operatingfrequency of a tap with higher frequencies is preferably closest to thehighest operating frequency of a tap with lower frequencies. Forexample, an operating band of the first branch tap 121 is 1 to 5, thatis, the lowest frequency of the first branch tap 121 is 1 Hz, and thehighest frequency is 5 Hz; an operating band of the second branch tap122 is 7 to 9, that is, the lowest frequency of the second branch tap122 is 7 Hz, and the highest frequency is 9 Hz; and an operating band ofthe third branch tap 123 is 12 to 15, that is, the lowest frequency ofthe third branch tap 123 is 12 Hz, and the highest frequency is 15 Hz.

The highest frequency 5 Hz of the first branch tap 121 differs from thelowest frequency 7 Hz of the second branch tap 122 by 2 Hz, and differsfrom the lowest frequency 12 Hz of the third branch tap 123 by 7 Hz. Inthis way, it may be determined that the coupling calculation frequencyof the first branch tap 121 is closest to that of the second branch tap122. When the first branch tap 121 is capacitively coupled, the secondbranch tap 122 is inductively coupled. Alternatively, certainly, it maybe that, when the first branch tap 121 is inductively coupled, thesecond branch tap 122 is capacitively coupled. The lowest frequency 12Hz of the third branch tap 123 differs from the highest frequency 5 Hzof the first branch tap 121 by 7 Hz, and the lowest frequency 12 Hz ofthe third branch tap 123 differs from the highest frequency 9 Hz of thesecond branch tap 121 by 3 Hz. In this way, it may be determined thatthe coupling calculation frequency of the third branch tap 123 isclosest to that of the second branch tap 121. When the second branch tap122 is inductively coupled, the third branch tap 123 is capacitivelycoupled. When the second branch tap 122 is capacitively coupled, thethird branch tap 123 is inductively coupled. In production, a couplingpolarity of each tap may be determined according to an ascending orderor a descending order. This is not limited herein.

FIG. 4 is a schematic structural diagram of an input/output apparatusaccording to an embodiment of the present disclosure. As shown in FIG.4, the input/output apparatus includes a main tap 11, a first branch tap121, and a second branch tap 122. The first branch tap 121 and thesecond branch tap 122 are respectively coupled to resonant cavities of amultiplexer. The first branch tap 121 is capacitively coupled, and thesecond branch tap 122 is inductively coupled. Capacitive coupling inthis embodiment of the present disclosure refers to a capacitiverelationship formed between a branch tap and a resonant cavity. As shownin FIG. 4, the first branch tap 121 is in no contact with itscorresponding resonant cavity, and capacitive space is formed, so as tobuild a capacitive coupling relationship between the first branch tap121 and its corresponding resonant cavity. Inductive coupling refers toan inductive relationship formed between a branch tap and acorresponding resonant cavity. As shown in FIG. 4, the second branch tap122 is in direct contact with its corresponding resonant cavity, andinductive space is formed, so as to build an inductive couplingrelationship between the second branch tap 122 and its correspondingresonant cavity. For understanding of a specific capacitive couplingstructure and a specific inductive coupling structure in this embodimentof the present disclosure, refer to prior-art capacitive coupling andinductive coupling schemes in other aspects, or the capacitive couplingstructure and the inductive coupling structure in this embodiment of thepresent disclosure may be new schemes developed later. This does notaffect application of the present disclosure and is not described indetail herein. In addition, in FIG. 4, a resonant cavity is indicated bya dashed line, meaning that the resonant cavity is a constituent part ofthe multiplexer instead of a constituent part of the input/outputapparatus.

Additionally, all branch taps may be arranged on one horizontal layer.Alternatively, one branch tap may be located on one horizontal layer,and there are layers whose quantity is the same as that of branch tapsin a vertical direction. Alternatively, one or more branch taps may bearranged on one horizontal layer, and there are at least two layers ofbranch taps in the vertical direction.

In the input/output apparatus of the multiplexer provided in thisembodiment of the present disclosure, a coupling polarity of the firstbranch tap is opposite to that of the second branch tap; and a couplingcalculation frequency of the second branch tap is closest to a couplingcalculation frequency of the first branch tap, so that two channels withclosest frequencies use different coupling polarities. Because thecoupling polarities are different, signals naturally do not interferewith each other, and signal interference between channels is eliminatedin principle.

FIG. 5 is a schematic principle diagram of a multiplexer according to anembodiment of the present disclosure. As shown in FIG. 5, themultiplexer includes: a main tap 11 and at least two first-level branchtaps 12 (three branch taps are shown in FIG. 1, but this does not limita quantity of branch taps of the main channel) that are in aninput/output apparatus, and a resonant cavity 21. Although not shown inFIG. 3, a mounting plate may be further included in the multiplexeractually, and the resonant cavity 21 is disposed into the mountingplate. Each of the at least two first-level branch taps is coupled to adifferent first-level resonant cavity 21. Three first-level branch tapsshown in FIG. 5 include a first first-level branch tap 121, a secondfirst-level branch tap 122, and a third first-level branch tap 123.Certainly, there may be only two first-level branch taps or morefirst-level branch taps. This is not specifically limited herein. Inthis embodiment of the present disclosure, three first-level branch tapsare used as an example for description.

A coupling polarity of the first first-level branch tap 121 is oppositeto that of the second first-level branch tap 122. A coupling calculationfrequency of the second first-level branch tap 122 is closest to acoupling calculation frequency of the first first-level branch tap 121.A coupling calculation frequency of a first-level branch tap is afrequency used in calculation to determine coupling polarities of thefirst first-level branch tap and the second first-level branch tap.

In this embodiment of the present disclosure, for a definition of thecoupling calculation frequency and how to determine the closest couplingcalculation frequencies, refer to descriptions corresponding to FIG. 3.Details are not further described herein.

FIG. 6 is another schematic principle diagram of a multiplexer accordingto an embodiment of the present disclosure. As shown in FIG. 6, themultiplexer includes: a main tap 11, and three first-level branch taps,which are respectively a first first-level branch tap 121, a secondfirst-level branch tap 122, and a third first-level branch tap 123. Apolarity of coupling the first first-level branch tap 121 to afirst-level resonant cavity 211 is opposite to a polarity of couplingthe second first-level branch tap 122 to the first-level resonant cavity211. As shown in FIG. 6, a polarity of coupling the first first-levelbranch tap 121 to the resonant cavity is capacitive coupling, and apolarity of coupling the second first-level branch tap 122 to theresonant cavity is inductive coupling. Certainly, it may alternativelybe that a polarity of coupling the first first-level branch tap 121 tothe resonant cavity is inductive coupling, and a polarity of couplingthe first first-level branch tap 122 to the resonant cavity iscapacitive coupling.

Among first-level resonant cavities 211, at least one first-levelresonant cavity 211 is connected to at least two second-level branchtaps. Each of the at least two second-level branch taps is coupled to adifferent second-level resonant cavity 212. The at least twosecond-level branch taps include a first second-level branch tap 221 anda second second-level branch tap 222.

A coupling polarity of the first second-level branch tap 221 is oppositeto that of the second second-level branch tap 222. A couplingcalculation frequency of the second second-level branch tap 222 isclosest to a coupling calculation frequency of the first second-levelbranch tap 221. A coupling calculation frequency of a second-levelbranch tap is a frequency used in calculation to determine couplingpolarities of the first second-level branch tap and the secondsecond-level branch tap.

In this embodiment of the present disclosure, for a definition of thecoupling calculation frequency and how to determine the closest couplingcalculation frequencies, refer to descriptions corresponding to FIG. 3.Details are not further described herein.

As shown in FIG. 6, a polarity of coupling the first second-level branchtap 221 to the resonant cavity is capacitive coupling, and a polarity ofcoupling the second second-level branch tap 222 to the resonant cavityis inductive coupling. Certainly, it may alternatively be that apolarity of coupling the first second-level branch tap 221 to theresonant cavity is inductive coupling, and a polarity of coupling thesecond second-level branch tap 222 to the resonant cavity is capacitivecoupling.

FIG. 7 is a schematic structural diagram of a multiplexer according toan embodiment of the present disclosure. FIG. 7 is a schematicstructural diagram of a hexa-plexer. As shown in FIG. 7, the multiplexerincludes a mounting plate 30, a first-level resonant cavity 211, and asecond-level resonant cavity 212. The first-level resonant cavity 211and the second-level resonant cavity 212 are both disposed into themounting plate 30. The multiplexer further includes a main tap 11, afirst first-level branch tap 121, and a second first-level branch tap122. A coupling polarity of the first first-level branch tap 121 iscapacitive coupling, and a coupling polarity of the second first-levelbranch tap 122 is inductive coupling. A boss 23 is disposed on themounting plate 30, and the boss is configured to physically and directlyconnect to a branch tap to the boss 23 when the branch tap iscapacitively coupled to a resonant cavity. In this way, capacitive spaceis formed between the boss 23 and a corresponding resonant cavity toimplement capacitive coupling. It may also be understood that a boss 23is disposed for a resonant cavity that implements capacitive coupling. Acorresponding boss 23 is disposed on each resonant cavity configured toimplement capacitive coupling. A tap capacitively coupled to a resonantcavity may be inserted into the boss 23 directly, so as to couple to theresonant cavity. Disposition of the boss 23 can facilitate mounting forcapacitive coupling. A specific position, method, and the like fordisposing the boss may be determined according to specific productrequirements, and are not limited herein. A material of the boss may bea conducting material, such as metal. For example, the boss may use asame material as a cavity body of the resonant cavity. For example, thefirst first-level branch tap 121 is capacitively coupled, and the firstfirst-level branch tap 121 is physically and directly connected to aboss 23 of the first-level resonant cavity 211 corresponding to thefirst first-level branch tap 121. That is, the first first-level branchtap 121 is directly inserted into the boss 23 of the first-levelresonant cavity 211 corresponding to the first first-level branch tap121. An adjustment screw 24 is further disposed on the mounting plate30. The adjustment screw 24 is configured to adjust coupling strength ofcapacitive coupling. That is, a depth by which the adjustment screw 24is inserted into the mounting plate 30 directly affects the couplingstrength of capacitive coupling.

FIG. 8 and FIG. 9 are both schematic structural diagrams of amultiplexer according to embodiments of the present disclosure. Themultiplexers shown in FIG. 8 and FIG. 9 may be layered in a verticaldirection. As shown in FIG. 8 and FIG. 9, when there are only twofirst-level branch taps, the two branch taps may be arranged in twolayers in a vertical direction, so that a horizontal area of themultiplexer can be reduced. An actual quantity of layers is not limitedto two, but can be specifically designed according to a quantity oftaps.

In the embodiments of the present disclosure, a physical structure ofopposite-polarity coupling is used to eliminate interference betweenchannels of a multiplexer in principle. Because the interference betweenchannels is eliminated, debugging difficulty can be greatly reduced, anddebugging efficiency of the multiplexer is improved.

Compared with a traditional solution, structures of the input/outputapparatus and the multiplexer that are provided in the embodiments ofthe present disclosure have simpler structures and are easier toassemble. Production difficulty can be reduced, and assembly efficiencyis improved. Additionally, coupling strength of a capacitive tap can beadjusted to allow for a greater assembly tolerance.

As shown in FIG. 10, a multiplexer provided in an embodiment of thepresent disclosure includes a resonant cavity.

When there are at least two levels of resonant cavities, each of atleast one first-level resonant cavity is coupled to a differentsecond-level resonant cavity via at least two taps. The at least twotaps include a first tap 221 and a second tap 222.

A coupling polarity of the first tap 221 is opposite to that of thesecond tap 222, and a coupling calculation frequency of the second tap222 is closest to a coupling calculation frequency of the first tap 221.

Optionally, the multiplexer may further include an input/outputapparatus. All taps of the input/output apparatus are directly connectedto the resonant cavity, for example, welded to the resonant cavity.

In this embodiment of the present disclosure, for a definition of thecoupling calculation frequency and how to determine the closest couplingcalculation frequencies, refer to descriptions corresponding to FIG. 3.Details are not further described herein.

As shown in FIG. 11, in a quad-plexer provided in an embodiment of thepresent disclosure, a main tap is directly connected to a first-levelresonant cavity. Four branch taps extend from the first-level resonantcavity, and each branch tap is coupled to a second-level resonantcavity. A polarity of coupling to the second-level resonant cavity isdetermined according to a coupling calculation frequency. Couplingpolarities of two branch taps with closest coupling calculationfrequencies are opposite. This eliminates interference between channelsin principle.

The multiplexer provided in any one of the foregoing embodiments of thepresent disclosure can be applied to, such as a radio frequency unit, abase station, a communications system, and a radar system in thecommunications industry. Any multiplexer-involved system or device thatuses the multiplexer provided in the embodiments of the presentdisclosure, or any multiplexer or other communications devicesmanufactured by using the solutions or principles provided in theembodiments of the present disclosure, can achieve the effects describedin the embodiments of the present disclosure.

The foregoing describes in detail the input/output apparatus of amultiplexer, and the multiplexer that are provided in the embodiments ofthe present disclosure. Although the principle and implementations ofthe present disclosure are described with reference to specificexamples, the descriptions of the embodiments of the present disclosureare merely provided to help understand the method and the core idea ofthe present disclosure. In addition, persons of ordinary skill in theart can make variations and modifications to the present disclosure withrespect to specific implementation and the application scope accordingto the idea of the present disclosure. Therefore, the content of thisspecification shall not be construed as a limitation on the presentdisclosure.

What is claimed is:
 1. An input/output apparatus of a multiplexer, theinput/output apparatus comprising: a main tap; and at least three branchtaps of the main tap, wherein each of the at least three branch taps isconfigured to couple to a different resonant cavity in the multiplexer,and the at least three branch taps comprise a first branch tap and asecond branch tap; wherein a coupling polarity of the first branch tapis opposite to that of the second branch tap, and a coupling calculationfrequency of the second branch tap is closest to a coupling calculationfrequency of the first branch tap relative to a coupling calculationfrequency of each of the other branch taps and the coupling calculationfrequency of the first branch tap, and wherein the first branch tapincludes at least a first first-level branch tap and the second branchtap includes at least a second first-level branch tap.
 2. Theinput/output apparatus according to claim 1, wherein an arrangement ofthe at least three branch taps comprises at least three layers in avertical direction.
 3. The input/output apparatus according to claim 1,wherein the first branch tap is capacitively coupled, and the secondbranch tap is inductively coupled; or the first branch tap isinductively coupled, and the second branch tap is capacitively coupled.4. A multiplexer, comprising: an input/output apparatus comprising amain tap and at least three first-level branch taps of the main tap,wherein each of the at least three first-level branch taps is coupled toa different first-level resonant cavity, and the at least threefirst-level branch taps comprise a first first-level branch tap and asecond first-level branch tap; a resonant cavity comprising a pluralityof first-level resonant cavities; and a mounting plate, wherein theresonant cavity is disposed into the mounting plate; wherein a couplingpolarity of the first first-level branch tap is opposite to that of thesecond first-level branch tap, and a coupling calculation frequency ofthe second first-level branch tap is closest to a coupling calculationfrequency of the first first-level branch tap relative to a couplingcalculation frequency of each of the other first-level branch taps andthe coupling calculation frequency of the first first-level branch tap.5. The multiplexer according to claim 4, wherein at least onefirst-level resonant cavity is connected to at least three second-levelbranch taps, wherein each of the at least three second-level branch tapsis coupled to a different second-level resonant cavity, and the at leastthree second-level branch taps comprise a first second-level branch tapand a second second-level branch tap; and a coupling polarity of thefirst second-level branch tap is opposite to that of the secondsecond-level branch tap, and a coupling calculation frequency of thesecond second-level branch tap is closest to a coupling calculationfrequency of the first second-level branch tap relative to a couplingcalculation frequency of each of the other second-level branch taps andthe coupling calculation frequency of the first second-level branch tap.6. The multiplexer according to claim 4, wherein an arrangement of thefirst-level branch taps comprises at least three layers in a verticaldirection.
 7. The multiplexer according to claim 4, wherein a boss isdisposed on the mounting plate, and the boss is configured to physicallyconnect to a branch tap directly when the branch tap is capacitivelycoupled to a resonant cavity.
 8. The multiplexer according to claim 7,wherein an adjustment screw is further disposed on the mounting plate,and the adjustment screw is configured to adjust coupling strength ofcapacitive coupling.
 9. The multiplexer according to claim 4, wherein:the first first-level branch tap is capacitively coupled, and the secondfirst-level branch tap is inductively coupled; or the first first-levelbranch tap is inductively coupled, and the second first-level branch tapis capacitively coupled.
 10. A base station, comprising a multiplexer,wherein the multiplexer comprises: an input/output apparatus, a resonantcavity, and a mounting plate, wherein: the resonant cavity is disposedinto the mounting plate; the input/output apparatus comprises a main tapand at least three first-level branch taps of the main tap, wherein eachof the at least three first-level branch taps is coupled to a differentfirst-level resonant cavity included in the resonant cavity, and the atleast three first-level branch taps comprise a first first-level branchtap and a second first-level branch tap; and a coupling polarity of thefirst first-level branch tap is opposite to that of the secondfirst-level branch tap, and a coupling calculation frequency of thesecond first-level branch tap is closest to a coupling calculationfrequency of the first first-level branch tap relative to a couplingcalculation frequency of each of the other first-level branch taps andthe coupling calculation frequency of the first first-level branch tap.11. The base station according to claim 10, wherein: at least onefirst-level resonant cavity is connected to at least three second-levelbranch taps, wherein each of the at least three second-level branch tapsis coupled to a different second-level resonant cavity, and the at leastthree second-level branch taps comprise a first second-level branch tapand a second second-level branch tap; and a coupling polarity of thefirst second-level branch tap is opposite to that of the secondsecond-level branch tap, and a coupling calculation frequency of thesecond second-level branch tap is closest to a coupling calculationfrequency of the first second-level branch tap relative to a couplingcalculation frequency of each of the other second-level branch taps andthe coupling calculation frequency of the first second-level branch tap.12. The base station according to claim 10, wherein an arrangement ofthe first-level branch taps comprises at least three layers in avertical direction.
 13. The base station according to claim 10, whereina boss is disposed on the mounting plate, and the boss is configured tophysically connect to a branch tap directly when the branch tap iscapacitively coupled to a resonant cavity.
 14. The base stationaccording to claim 13, wherein an adjustment screw is further disposedon the mounting plate, and the adjustment screw is configured to adjustcoupling strength of capacitive coupling.
 15. The base station accordingto claim 10, wherein: the first first-level branch tap is capacitivelycoupled, and the second first-level branch tap is inductively coupled;or the first first-level branch tap is inductively coupled, and thesecond first-level branch tap is capacitively coupled.